Penises (with Emily Willingham)

How does the human penis measure up to the rest of the animal kingdom? What can the shape of the penis tell us about human mating? And what is up with society’s obsession with the penis?

Today’s guest is Emily Willingham, science journalist and author of the book “Phallacy: Life Lessons from the Animal Penis.”

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Taboo Science is written and produced by Ashley Hamer. Theme music by Danny Lopatka of DLC Music.


003 Penises

Ashley: Like a lot of women, I’ve spent my life in male dominated spaces. I went to college for music, jazz specifically, which is absolutely overrun with men. I’m happy to see that that’s changing, but during my time at music school, I was one of just a handful of female jazz saxophone players, and that’s why for years, I could not avoid hearing metaphors about male genitalia.

Was there a loud section in the music? Well, you gotta play it with balls. Was there a long building crescendo? Don’t blow your load before the climax guys. Did someone play an amazing solo? Man, he just put his dick on the table. Are the musicians playing with too much technique and not enough artistry? Ugh, it’s just a pissing contest.

The obvious problem here is that I, well, don’t have a penis. The language was so widespread that I’d use it too. Sometimes to understanding nods, sometimes to strange looks. It was a gamble. I never knew which one I was gonna get.

There are no female-centric terms for these things. I mean, people are trying, but when you say something like that, took ovaries of steel, it sounds more like a cheeky novelty than an actual expression of bravery.

There are a lot of reasons for this, but one is that society absolutely worships the penis. Having a big one means you’re a real man, powerful and secure in your lofty place in life. Having a small one is a weakness and people are constantly looking for signs of this weakness. Have a big truck or a fancy sports car? Hmm. Must be compensating for something. Being violent or racist or destructive. Ugh, that’s small dick energy. Did some jerk post something sexist? Better insult the size of his package to get back at him.

It goes without saying that people without penises, therefore, are weak by default. Why is that? I mean, why do we elevate this fleshy organ to such heights, and how does this outsized importance harm the human being attached to it, not to mention the human beings around it. That’s what we’re gonna find out today.

I’m Ashley Hamer, and this is Taboo Science.

To explore why we give the penis MVP status. I mean that, that obviously stands for most valuable? Question mark? Penis. I turned to Emily Wilingham. She’s a science journalist and author who has, well, a PhD in penises, a doctorate in Dicks, a JD in junk. Okay. That would technically make her a lawyer. I’ll, I’ll just let her tell you.

Emily Willingham: I have a PhD in gonads. I studied reproductive biology and then I went on to do a postdoc in penises. And so we actually studied how they develop and what influences that. And it’s incredibly interesting. When you look around at what’s going on in the world right now and the way people are using penises and you think you know, you’re overrating these.

And maybe it’s time to kind of put them where they belong on the spectrum among animal penises. And that’s where this book came.

Ashley: The book Emily Willingham wrote is called Phallacy — that’s with a “ph” — Life Lessons from the Animal Penis.

So why do we consider the penis to be the be all, end all of organs?

Emily Willingham: We really, we spent a long time placing it that way, centering it that way. This is a broad history, but right about the time we started really settling in geographically and establishing agriculture instead of doing more of the gathering as you go kind of situation, there’s an intersection there of fertility and protection and the use, the rise, as it were of the phallus as a symbol of that, of both of those things.

An example would be the Egyptian God Min, m i n, who, one of the very first of these types of deities, and he’s presented holding a flail, which is something that you used to harvest grain in one hand. But he is also presented with a very erect phallus. It is erect parallel to the ground, and his use was both as a protector and a fertility god for, you know, let’s please everything grow like we want it to. And also please nothing destroy it before that happens.

And his plant symbol is possibly, kind of surprisingly, was lettuce, a kind of lettuce that takes a sort of a phallic shape of its own. It’s not like a iceberg , right? . And this kind of lettuce, when you break it, it oozes a white fluid. And so that came to be associated as his sort of sacred plant.

Ashley: Around the same time, people would put up images of the Roman deity Priapus and his permanently erect penis to guard orchards and gardens, and Roman children would ward off danger by wearing a fascinum around their necks. Basically a penis pendant.

The ancient Greeks meanwhile considered large penises to be barbaric and laughable. That’s opposite to Western attitudes today, but it still reduces a person’s character to the influence of the single organ.

Emily Willingham: And from there, we took off with it. It became to the point where they basically kind of took away the whole body and just left the penis itself as the protector or the threat.

Ashley: But with great power comes great anxiety.

In Europe, a fear of lower members of society robbing prominent men of their power led to anxiety about penis stealing. One of the greatest sources of this anxiety came with a 1487 publication of the Malleus Maleficarum, or the Hammer of Witches.

Emily Willingham: The primary author on it was a priest who’s last name was Kramer, and he seems to have had some baggage that he brought to it. But he had this, this still remains a common concern, there’s a, a long tradition of, oh my god, the women are going to wave their hands and the penis will vanish. And so he’s got, you know, for example, stories in there of penises just disappearing and giving advice for how men might go about trying to get them back and that kind of thing.

And then of course, just, you know, it’s called the Hammer of Witches because it’s intended as a list of rules of how you, what you do with witches, which typically involves horrible physical harm and death. And a lot of it had to do with their behaviors with the devil and his raging erection. So.

Ashley: You heard that right. In Kramer’s version of things, the devil has this massive erection that witches just can’t resist. And in fact, it’s this book that turns witchcraft from something that anyone could be accused of to something that only women did. Because they were out to steal men’s penises. Women were actually convicted of this crime.

According to Dr. Willingham, this book may have served as the basis for tens of thousands of deaths. In some regions of the world, penis stealing is still something people can be accused of today.

We’ll get back to messed up beliefs about the penis later. But first, let’s back up into some boner basics. What is a penis biologically speaking?

Emily Willingham: It is a fleshy organ, and the part that probably matters the most is the part that gets diffused and stiff. There’s a spongy tissue, and when there’s arousal, the blood vessels kind of relax a little and let a lot of blood in which, you know, stiffens up the organ as it were. And, um, that is of course, the basis of Viagra is that it allows that to happen. It kind of maintains it for a while. Overcoming any, you know, other inhibitions somebody might be feeling consciously or otherwise.

And it’s different. You know, ours, it’s a kind of typical mammalian anatomy and when you start to look around at what other penises are made out of you realize, oh, that’s not, it’s kind of boring, honestly.

Ashley: Yeah. For all the love we have for the one-eyed trouser snake, it’s basically the Honda Civic of penises. Other animals have monster trucks, DeLoreans, pogo sticks, that war rig from Mad Max. I mean, some of it is honestly terrifying.

But before we get into that array of animal organs, a quick terminology note. There are actually a lot of different names for these organs in different species. So to simplify things, Dr. Willingham came up with her own singular term.

Emily Willingham: So in the book, I decided to settle on a single unifying concept of these organs that are inserted, which is in intromission is our fancy word for that. And so I decided to call them singly intromittum and, and the plural intromitta so that we don’t have to call them 5,000 different names. And insects make intromitta out of just all kinds of things.

They sort of can make some functional organs out of the plates on their thorax. They have organs that unfurl, uh, from the flea, for example, that’s, you know, much, much longer than the flea itself and kind of unfurls from the flea, from inside of it. They have organs, that are described as hypodermic, that they just sort of jab into the partner wherever, although seems like most of the time on the thorax and transmit gametes.

Insects are just all over the place with this. Um, arachnids as well. Spiders use specialized organs called pedipalps at the front. If you look at spiders, you can kind of tell it’s a male maybe some of the time at least, because they have these little sticks in the front that have these little boxing glove like ends on the front, on the ends of them, and that’s actually their version of intromitta.

Ashley: Right, which you, which you call in the book intromittens, which I love.

Emily Willingham: That’s probably gonna make a lot arachnologists mad at me. But they are, they look like little intromittens and so that’s what I decided to call them.

Ashley: That’s great. So what can the shape of an animal’s penis tell us about it?

Emily Willingham: Yeah, this was kind of actually one of the guiding, um, themes in the book for me was I think humans like to make a very big deal out of our penis. It’s like, wow, look at that thing.

But when you start to kind of look at shapes and sizes and what they mean, ours is fairly featureless. You know, it’s, it’s tons of fun. I don’t mean to diminish that at all, but when you start to look at it in the broader context of the animal kingdom, you realize that the more features they have, like spikes and pointy bits, and then the other things that look like cacti or brushes and that kind of stuff, that that means there’s something more specific and potentially with tension going on between the mating partners a lot of the time.

Ashley: By tension, she means like the act is not totally consensual.

Emily Willingham: Seed beetles are an example I used throughout the book. Their reproductive tactics involve you know, the male sort of jabbing. And there’s a seed beetle intromittum that looks a lot like a steel brush, and he inserts that into the female and it does leave marks on her genital tract and, and that doesn’t sound relaxed. It sounds like there’s some tension there.

Ashley: If you’ve done any Googling of animal penises — what, just me? — then you’ve probably seen the horror that is the duck penis. That’s a classic example of not only tension, but an incredible evolutionary arms race.

Emily Willingham: In some duck species, the male has a penis that will burst out of him with kind of a ballistic force. And it also has shape to it. It’s like, you know, a cork screw and exceptionally long. And so forceful cork screw is not something that humans have. Some male ducks have this because the female is not particularly consensually involved in the process, and so he tries to mount the female and use this ballistic, forceful corkscrew penis to get his part of the business done without, you know, her being super okay with it.

And what you see in response, and this is also distinctly not particularly human, is that the female ducks have vaginas that are pretty complicated. They have cul-de-sacs, these sort of blind ends where you know, the male can do what he wants, but the sperm just ends up going nowhere. And they also, in some cases, are reported to have anti corkscrew vaginas that kind of unscrew in the opposite direction of the male’s corkscrew penis. That’s tension. That implies that there’s tension and there’s some force going on there. Our genitalic setup is not like that.

Ashley: But the fact that the human penis isn’t a biological Swiss army knife suggests that we’re set up for a lot less tension when it comes to how we mate. Instead, we, like other animals in possession of basic boneage, have to work to make sure everyone involved is an interested and enthusiastic participant.

Emily Willingham: There are some species where the intromitta they use don’t have a lot of bells and whistles or features, and they are species and there’s like some insects or arachnids and things like that that have a very, very carefully choreographed mating process that they go through. Everybody has to hit their mark at every step of the way, or it doesn’t happen. You know, they don’t have all these specialized features, but they sure do have a lot of requirements for the mating ritual.

Ashley: Wow. So that basically the, the more boring the penis, the fancier, the uh, the wooing, I guess.

Emily Willingham: Yeah, the, yeah. It’s kind of more stringent wooing requirements. You know, you got to get consent there in an insect kind of version of it every step of the way. You did that right. That’s exactly right. Yep. We may move forward now. You know.

Ashley: Right? And there’s, and there’s consent on both sides in that case.

Emily Willingham: Yes. Yes. Both of them are like recognizing one another’s signals and giving the go ahead.

Ashley: The idea that biology dictates that our mating style requires flowers and candles, or at least pizza and an Uber, kind of flies in the face of some common beliefs about how ancient humans behaved. I mean, we’ve all seen the classic image of a caveman dragging a woman to the cave by her hair. Ooh. Now that’s tension.

But there are plenty of other animal comparisons that conflict with this idea too. I mean, chimps and orangutans don’t generally ask for permission before mating, and they’re close relatives to us. So how does the spider penis give a more accurate lesson about human mating than non-human primates do?

Emily Willingham: There’s a tendency in a certain corner of research, evolutionary psychology research, I think biologists fall into this trap as well, where there are behaviors that you want to rationalize in some way. And so you want to say they’re natural because that makes it sound like, well, you know, if you’re natural, hey, what are you gonna do? I’m just being natural, right?

And so you’ll find these examples in nature and use them as exemplars and say, well, this explains that, and therefore what I’m doing is fine. It’s natural. The problem with that is, and it’s distinct from what biologists would do, say if they’re using an animal to model something like they do with mice and disease. You know, it’s just kind of a starter point for, you know, well, if we tweak this gene, then what happens to the mouse? Well, if humans have a similar gene, perhaps this might explain the trait linked to this gene and how it might change with different variants. Something like that.

This is exact — you know, I don’t take bonobos or even, you know, which are our closest living relatives, bonobos and chimpanzees. You can’t look at them and go, look how they’re acting. That explains us. We’ve been separated with 5 or 6 million years of evolution, and we can look at what they’re doing and think maybe at that time, at that split, some ancestral human species maybe was doing that too. But that doesn’t mean that’s why we’re doing what we do now.

And looking at the human penis among all these other animal penises, just is to pull patterns out. Not to use a specific example, but to say, look at these animals with fairly featureless intromitta, right? And how they behave, what their mating rituals are like, or what their copulation experience is like. Their strategies. Look at these animals here with these much more striking, to us, extremely interesting organs and what the partners’ features look like as well, and how they illustrate that there’s some kind of a tension there. And you can see from ours that evolutionarily speaking, if it follows this pattern, there’s not a lot of tension there shaping either the vagina or the penis in humans. And our issue is we are sui generis. So we have no other member of our genus, we are it. So if we were really looking for examples of us, we are our example and we don’t have anything closer to us than 5 or 6 million years of evolution separating us.

Ashley: That brings a question up. Do we know anything about ancient human penises?

Emily Willingham: Yeah, it’s a good question. So there’s a part of the book, I talk about the spines and the fact that although a lot of primates do have them, penis spines is what I mean, right?

Ashley: Yep. Penis spines in pretty much every non-human primate and many other mammals for that matter, the penis is covered with these hard spikes.

Sometimes they’re small, like little penis jewels. Sometimes they’re more like the spines of a small cactus. But humans don’t have penis spines. No dick bedazzling for us.

Emily Willingham: We don’t because of a change, a DNA variant that we have that is related to production of these, and we have been able to not, you know, somebody has been able to go look at Neanderthals and Denisovans or Denisovans. They’ve gotten enough DNA to find that they too had this variant. And so it’s very likely that they did not have these spines, either. These little bumpy things on the penis, which kind of makes sense because as we know, we did occasionally get it on with Neanderthals. And so we had, you know, reasonably good generalist match there between vagina and penis with them.

Ashley: Another feature that we don’t share with our primate cousins is the penis bone. Technical name, baculum. Plural, bacula. Relation to actor Scott Bakula of the hit show Quantum Leap, none. That we know of.

Lots of mammals have a baculum, including bats, raccoons, dogs, bears, hedgehogs, walruses, otters, rats and mice, and almost all primates. Save for the handful that includes humans.

This bone sits along the end of the penis above the urethra, unconnected to any other bones in the skeleton. Scientists think it may help mating, well, last longer, evidenced by the fact that primates with a baculum tend to mate for three minutes or more on average.

Because, uh, human males tend to last about two minutes on average. It’s science. I’m sorry.

If it makes you feel any better, a 2004 study found that this doesn’t actually bother female partners as much as it bothers the men.

It’s important to bust the sex myths that are floating around in general society, but scientists through time have believed in their own myths. The most infamous penis obsessed scientist of all, of course, is Sigmund Freud. Freud believed that as children develop, they go through different psychosexual stages where their pleasurable drives are focused on a different part of the body.

So until you’re one year old, you’re in the oral stage. One to three year olds are in the anal stage. Between three and six, you’re in the phallic stage. According to Freudian analysts, this is the stage when all sorts of messed up stuff can happen. Boys can develop an Oedipus complex where they have sexual desires for their mother and fear castration by their father.

Girls can develop an Electra complex where they have sexual desires for their father, realize that they themselves don’t have a penis like dad does, and then develop penis envy. If you think that’s weird, just wait until you hear the kinds of things Freudian analysts did with all these ideas.

Emily Willingham: I have a couple of stories in that last chapter where people are applying this Freudian psychoanalysis and one, one therapist has decided that his patient has decided that he, he wants the therapist to be his phallus. And I, something to the effect of, you know, he wants to eat the therapist because the therapist is his phallus and all this other stuff. And I’m just thinking, dude, really, right. You got stuff to work out there clearly.

But that’s, you know, amusing on its face. But there’s some deeper harms. There are, there’s a paper I discuss in there, a therapist who’s sort of trying to apply these Freudian ideas to what he calls phallic girls. Women who you know, Sylvia Plath wrote about this, not allowed into men’s spaces, and that’s really all they wanted was to be able to do what the men were doing and not necessarily that they felt that they themselves were men.

This man interprets this is, these women were, in some ways they wanted to be men, and that when they had children, they wanted to turn their children into little phalluses. And he manages to basically distort every single typical normal, healthy maternal behavior and turn it into something phallic. It’s pretty nauseating.

Ashley: That’s kind of blatant, but science’s focus on the penis has done some more insidious things that have slipped under the radar, like the fact that all this focus on the penis has left scientific research with scraps about

the vagina.

Emily Willingham: The other message of the book is that because we focus so much on penises, because we have spent so much time on them, we have neglected vaginas. We have neglected the other side of that equation a great deal, and it certainly deserves more attention. In fact, I centered that chapter in the book on purpose , because I wanted to be right there in the center.

Ashley: Yeah, actually, let’s talk a little bit more about how little research we have on vaginas, because clearly I probably can’t even do a whole episode on vaginas.

We know so little about them.

Emily Willingham: You, you probably could now, cuz there are a couple, there’s certainly, about human vaginas, so finally some books that really address it. But in terms of just the zoological research, it’s, there’s a deficit. And I’m not just saying that because you know, I’m like down with the patriarchy or anything like that.

There’s just a deficit. And when you drive scientific studies that show that we’re still not focusing enough. One of the books I used a lot in my research for this was one that was written in 1985. That was the first one to really take that side, to look at that side of things at the vagina side of things, right?

And here we are 35 years later and there’s still papers published in 2018, 2019, saying, we just aren’t looking at this enough. There’s just not enough data out there about it. There are so many things feeding into that from taxonomists really focusing on, um, male genitalia in insects because they were using that also to try to assign species in a lot of cases.

So that just introduces a bias right there. But a lot of it is, is that the people who have been asking these questions over the last couple of centuries and answering them, have not been people who have had vaginas. And so they just turn their focus where they are most interested. The result is we get language that even if it’s an anatomical structure on an animal that’s female, it gets often couched in the context of the structure that’s on the male.

Like hyenas. They’ll describe — the hyena has extremely long clitoris. They’ll describe it as male-like, or, you know, phallus-like and all this other stuff. And I feel like if people with vaginas have been in charge this whole time, maybe we would reverse that and describe a sort of not as long penis in some species as being more clitoris-like, you know, I don’t know.

Ashley: Right? Yeah.

But above, just like leaving out vaginas in research, what, what have we learned that we wouldn’t have learned otherwise? In the few cases where we studied vaginas, what have we learned?

Emily Willingham: So this question of, you know, is there tension in the mating or not? That question is best answered by looking at both sides of the mating equation, because if tension manifests as changes in a penis, in an intromittum, then you should also see changes, right, if this is a back and forth evolutionary selection arising from this tension, then you should see some changes in the vagina as well. But a lot of the time that side of it doesn’t get looked at. And I quote from the literature people saying, eh, it’s probably not that interesting. It’s probably not much going on.

But the thing is, is that they’re saying these penises are different because there’s something going on. And that implies that then they, you should look at the vaginas because there’s probably something different going on there as well. There’s an argument to be made for basic research like this. Basic research, meaning research for the sake of discovery, for the sake of knowledge.

Because if you gain an understanding about species and their mating and what happens on the ground there, that can later have implications for like conservation biology or what we understand about climate change and a lot of other things. But if we never look at, we’re leaving out half the species, in a lot of cases.

Ashley: In a way, we’re leaving out more than half the species because when we give the penis this much importance and power, we simplify the person attached to that penis.

Emily Willingham: It’s interesting because we treat the penis almost as though it does have a mind of its own, which it does not. I, you know, would like to reinforce that our minds are in our heads, it’s our brain. And there are all kinds of things that we do to reinforce a wedge between penis havers and non penis havers, and the threat that is posed to the penis itself, that it will be cut off or it will be stolen, or you know, that it’s not big enough or that it’s a funny shape.

Just so many things that get aimed at this organ as though it were the be all and end all and superseded all else about the human who has it. And we still do that today politically. You know, we see a guy walking around with an AR 15 in a Starbucks and people will say things like small dick energy and things like that.

And that’s a human there doing that with their, you know, complex cultural reasons and social reasons behind why that guy thinks he needs to do that and perform that way. And it’s got a lot more to do with than whatever the contours of his penis are. It is so important to pay attention to the whole person and not just that feature, and we really do tend to home in on the penis just at every turn and focus on it and obsess about it, and it’s detrimental.

It’s detrimental to the people who have them and their sense of themselves and their place in the world, and it’s detrimental to the people who have relations with them.

Ashley: Thanks for listening. Taboo Science is written and produced by me, Ashley Hamer. The theme was by Danny Lopatka of DLC Music. Tons of thanks to Emily Willingham. Her book, Phallacy: Life Lessons from the Animal Penis, is out now and you can find a link to pick it up in the show notes. You can follow Taboo Science on Twitter, Facebook, and Instagram.

Just look for Taboo Science, all one word, or just visit the website to find it all in one place. That’s at If you liked this episode, I’d really appreciate it if you could leave a review on Apple Podcasts. I have a long list of taboo topics that I want to cover on future shows, but if you wanna suggest one, email

PS: I am absolutely doing an episode about vaginas, so keep an eye out for that. But the next episode is a big one. It was actually number one on my list when I was first planning this podcast, and it does not disappoint. You can expect that one in two weeks. Stay tuned.